Generally, some known radar systems achieve angle coverage with multiple signal beams, depending upon the application with which the radar system is used. In such radar systems, a switched beam or mechanically scanned antenna can be incorporated, which can limit performance in one or more ways. One example of such a conventional radar system generally having limited performance is a mechanically scanned antenna that has an update rate that is too slow to achieve wide angle coverage for a particular application. Switched beam radar systems can achieve high update rate, but the number of beams is often limited, resulting in either angle coverage that is too narrow or a beamwidth that is too wide for particular applications.
Electronically scanned antennas can generally be employed with radar systems. A radar system having an antenna that electronically scans can generally allow for fast scanning, the ability to host multiple antenna beams on the same array, a wide field of view, a narrow beam, and a high update rate. However, electronically scanned antennas typically use discrete phase shifters that are expensive and can introduce excessive radio frequency (RF) loss at particular frequencies, such as 24 GHz and 76 GHz, for example, in automotive radar systems.
In addition to the excessive RF loss at particular frequencies, using discrete phase shifters can be undesirable in an automotive application due to the cost of such a radar system. Other examples of deficiencies of radar systems used in automobile applications are a limited field of view, an insufficient update rate, inaccuracy, lack of multi-target discrimination, lack of stopped object capability, and inadequate false alarm rates.